Bifidobacterium adolescentis is intrinsically resistant to antitubercular drugs.

Lokesh, Dhanashree and Parkesh, Raman and Kammara, Rajagopal (2018) Bifidobacterium adolescentis is intrinsically resistant to antitubercular drugs. Scientific reports, 8 (1). p. 11897. ISSN 2045-2322

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Multiple mutations in the β subunit of the RNA polymerase (rpoβ) of Mycobacterium tuberculosis (Mtb) are the primary cause of resistance to rifamycin (RIF). In the present study, bifidobacterial rpoβ sequences were analyzed to characterize the mutations that contribute to the development of intrinsic resistance to RIF, isoniazid, streptomycin and pyrazinamide. Sequence variations, which mapped to cassettes 1 and 2 of the rpoβ pocket, are also found in multidrug-resistant Mtb (MDR Mtb). Growth curves in the presence of osmolytes and different concentrations of RIF showed that the bacteria adapted rapidly by shortening the growth curve lag time. Insight into the adapted rpoβ DNA sequences revealed that B. adolescentis harbored mutations both in the RIF pocket and in regions outside the pocket. The minimum inhibitory concentrations (MICs) and mutant prevention concentrations (MPCs) indicated that B. longum, B. adolescentis and B. animalis are resistant to antitubercular drugs. 3D-homology modeling and binding interaction studies using computational docking suggested that mutants had reduced binding affinity towards RIF. RIF-exposed/resistant bacteria exhibited variant protein profiles along with morphological differences, such as elongated and branched cells, surface conversion from rough to smooth, and formation of a concentrating ring.

Item Type: Article
Additional Information: Copyright of this article belongs to NPG.
Uncontrolled Keywords: Cellular microbiology; Microbiology
Subjects: Q Science > QR Microbiology
Depositing User: Dr. K.P.S.Sengar
Date Deposited: 18 Mar 2019 17:07
Last Modified: 18 Mar 2019 17:07

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